The present invention relates to a prosthetic joint, and in particular to a prosthetic joint having diamond-coated load-bearing surfaces to thereby reduce friction and increase the useful life of the joint.
The use of prosthetic joints to replace joints which have either been worn out or damaged in an accident has become commonplace. The use of prosthetic joints has allowed many people with severe joint problems to return to activity, and enjoy a relatively normal lifestyle. While prosthetic joints have been used in numerous applications, the most common are those used to replace knees and hips which have either worn out, been fractured, or otherwise been damaged.
The primary problem with prosthetic joints is that the joints eventually erode and must be replaced. This erosion is caused, in large part, by the forces of impact and friction routinely encountered by the load-bearing surfaces of the prosthetic joint. As the joint is repeatedly used, the ball and socket (in the case of a hip prosthesis) wear against each other. The impact and friction forces eventually cause pieces of the load-bearing surfaces to spall and float about the joint. This debris initiates a hystiocytic reaction in which the body's immune system is activated and releases enzymes to dissolve the particles. However, because the debris is usually relatively hard material, such as metal or polycarbon compounds, the enzymes usually fail to dissolve the debris, or take a considerable amount of time to do so. To further complicate matters, the enzymes react with the bone supporting the prosthetic joint. The enzymes weaken or dissolve the bone. This condition causes osteolysis or weakening of the bone, therefor weakening attachment to the bone and making it difficult to replace the prosthetic joint when the bearing surfaces have eroded to such a point that the joint should be replaced. Osteolysis decreases the lifetime of the replacement prosthetic joint, and eventually renders the bone unusable.
Thus, there is a need for a prosthetic joint that will function the remainder of the life of the recipient without osteolysis. The present invention accomplishes this by introducing long wearing, low friction, diamond-coated bearing surfaces, thereby decreasing the amount of debris eroded into the joint, so as to extend the life of the joint.